Trinuclear cyanine dyes



Patented July 19, 1949 UNITED ESTAT S 'TRINUCLEAR CYANINE DYES Alfred .W. Anish, Nestal, and Charles A. Clark, :Binghamton, N. Y.., assignors to General Aniline -i&- -Film Corporation, 1 r I poration of Delaware New :York, N. Y., a cor- No Drawing. 'Application'August15, 1946, 7

Serial No. 690,-8-32 11 Claims.

This invention relates. to .newdyes of the tri-, nuclear cyanine type; to a method of preparing thempland to photographic light-sensitive silver halide emulsions containing the same.

Cyanine dyes .containingmore than twonuclei are already known. Dyesaof this category are illustrated, for example, inUiS.v Patent 2,155,475, and in'French'Patent"832,352. It will be noted that in the dyes referred to in theUnitedStates patent the nucleus appearing in thejdye, in addition to the two terminal nitrogenous heterocyclic nuclei,'is aromatic in'character; Onthe other hand, in certain of the dyes of the French patent, the meso nucleus is heterocyclic and .of the type known a rhodanine nucleus. In both types of dyes,'however, the meso nucleus serves to in-' terrupt the methenyl chain by which the terminal heterocyclic nitrogenous nuclei are linked together.

Rhodacyanine dye salts, which. contain. in the polymethine chain-a rhodanine ring, are also known. .Thesedye'salts are prepared by first alkylating a suitable merocyanine and then con densing the alkylated product with a-cyclammo- Ilium quaternary salt. In this condensation reaction, the alkylmercapto group of the alkylated merocyanine condenses with, the methyl group attached in e-position to thenitrogen atom,,of. a" cyclammonium quaternary salt to give the desired dye :salt. Y

Trimethine dyestuffs containing an oxa dia-zole, substituted by a turanringware also known. Itisalso :known that cyanine dye con-' densations may :be carried out through an active amino 'group of a cyclammonium :base or salt toyield dyes of the :azamethine type. The simul-- taneous condensation, however, of bothan amino and a methyl groupof an oxadiazole or thiadiazole compoundwith .acyclammonium dye salt to yield trinuclear cyanine dyes has not been pre- 4 viously suggested or described.

We have now discovered a new classof trinuclear cyanine dye salts in :which thecentral nucleus, diazole 'or triazole, is linked to the other panchromatic film emulsions; but are also excellent sensitizersfor color. film, being. unaffected .Iby' thepresence .of color components, and exhibiting the property of non-migration from the layer. in which they are incorporated. Moreovenwe have found that these new dyes have appreciable water solubility and. are readily removed from the. exposed emulsion layer during processing.

It'is an object .of the. presentinvention to provide a new class of trinuclear cyanine dyes .con-

taining. a diazole or .triazole nucleus.

Another object is tel-provide amethod of preparing such dyes.

A further object is to provide alphotographic 15 element. comprising asilver-halideemulsion sensitized with the saiddyes.

Other obj ects. and advantages of this inven-v tion will become apparent by reference to the following specification in which its preferred details and embodiments .are described.

This invention is predicated upon our discovery that 1 mol of a 3,4-diazole or 1,3,4-triazole salt, containing an amino group in 2-position and a methyl group in 5-position with the nitrogen atom-in -position substituted by an alkyl or aralkyl group, "can be condensed with 2 mols-of'anitrogenous heterocyclic dye salt of the type used in cyanine dyes. is wholly unexpected and-surprising, since 3,4- diazole and 1,3,4-triazole salts, with the N atom in 3--or age-position substituted by an alkyl or aralkyl group and containing methyl groups in the 2- and fiepositionsare only-reactive through one of these groups i. e., through the methyl group in the 2- or 5-position, but not through bothgroups. Similarly, 3,4-diazole or 1,3,4-triazole salts containing an amino group in 2-position and a methyl group in 5-position, and wherein the nitrogen'at'om in 3-position is substituted 0 by an alkyl or aralkyl group, are reactive only through the amino group.

The trinuclear cyanine dyes prepared according to the present invention are characterized by the following general formula:

two nuclei by both a. methine andan azamethinechain. These new .dye salts have properties which are not possessedby .the known trinuclear. dye salts. .For instance. the dyes are not only ex-I.

wherein A represents the atoms necessary to complete a nitrogenous heterocyclic system of the type used in the preparation of cyanine dyes, such as, for example, .oxazole, oxazoline, thiazole; cellentsensitizers for .both. .orthochromatic and thia zoline, :selena zole, .selen a zoline, benzothiazole,

This discovery benzoselenazole, benzoxazole, naphthothiazole, naphthoselenazole, indolenine, pyridine and its polycyclic homologues such as quinoliner and naphthoquinoline, and the like. The polycyclic compounds of these series may also be substituted in the carbocyclic rings with one or more groups, such as alkyl, as below, aryl, i. e., phenyl, etc., amino, hydroxy, alkoxy, e. g., methoxy, ethoxy, propoxy, etc., and methylenedioxy groups. R is a hydrocarbon group, for example, alkyl group, e. g., methyl, ethyl, propyl, butyl, amyl, and the like, or aralkyl group, e. g., benzyl,;phenylethyl, and the like, X represents an anionic acid radical, e. g., C1, 131', I, C104, SO-iCHs, 1 SO4C2H5, SO3CsI-I4CH3, and the like, Y represents either m e r c a p t o, ethylmercapto,

' '2, and alkyl or arylmencapto radical when m is oxygen, sulfur, or NR2, wherein R2 is either hydrogen or an alkyl of the same value as R, an represents 0, 1, or 2, and p represents 0 or 1.

- As examples of representative cyclammonium quaternary cyanine dye salt intermediates falling within the above configuration the following may be mentioned;

' 4,5-diphenyl-3-ethyl-2-methylmercapto thiazo- The process of preparing the above trinuclear cyanine dyes comprises condensing, at room temperature or by heating as on a steam bath or under reflux conditions, 1 mol of a cyclammonium quaternary salt of 2-amino-5-methyl-3A-diazole,

or 1,3,4-triazole with 2 mols of a cyclammonium quaternary cyanine dye intermediate, of the type used'in the preparation of cyanine dyes, in the presence of an acid binding agent such as a nitrogenous heterocyclic base containing a small quantity of a tertiary base which may include a small quantity of acetic acid or acetic anhydride.

The anions of the dye salts thus obtained are readily converted into difierent anions by methods well-known in the art.

The cyclammonium quaternary salts of 2-almino-5-methyl-3A-diazoles and 1,3,4-triazoles utilized in the condensation reaction are characterized by the following general ltormulaz R N. l L3 4 HzN 2 1 5 -CH:

wherein R, X and Y have the same values as above, and are obtained by quaternizing any one of the following di-azoles as will be pointed out hereinafter.

ll HaN- C-CH; J. Prakt. Chem. 122,

2-amino-5-methyl-1,3,4-oxadiazo1e 1 HzN3 (k-GH; Ber. 29, p. 2513-4 7 S 2-amino-5-methyl-1,3,4-thiadiazole N--N H I; H:N-C CH Ber. 26, 2 599 2-amino-5methyl-1,3,4-triazole linium iodide 2- [.fl-anilido vinyll -3-ethyl-4-methyl thiazolinium iodide 1-ethyl-4-methylmercapto quinolinium iodide 3-ethyl-2-methylmercapto pyridinium iodide 2- [,B-anilidovinyl] -3,3-dimethyl-1-ethyl indoleninium iodide 2 [4]-acetanilidobutadienyl-3-ethyl-6-methoxy benzothiazolium iodide 2 ,8- acetanilidovinyl] -3-phenoxyethyl benzothiazolium iodide 2- [4] -acetanilidobutadienyl-3-ethyl benzoselenazolium iodide 3-ethyl-2-[p-methylmercapto vinyl] benzoselenazolium iodide 2 [,B-acetanilidovinyl]-3-ethyl-naphthothiazolium iodide 2- ,B-anilidovinyl] -3-ethyl benzoxazolium iodide 4-cyano-1-ethy1 quinolinium idodide 2- 8- acetanilidovinyl] -3,3 -dimethy1- l-ethyl indoleninium iodide 3 ethyl 2 [4 methylmercapto blutadienyll- 5-phenyl benzoxazol-ium iodide 2- [p-anilidovinyll -3p-methyl-thiazolinium iodide 2 [,8 anilidovinyl]-3-ethy1-4,5-benzo-lbenzoxazolium iodide 2- fl-a'cetanilidovinyll -3-ethy1-oxazolium iodide 2 [f3 acetanilidovinyll 3 ethyl-selenazolium iodide 1 2- [fl-acetanilidovinyl] -3-ethyl-4l,5-benzo -b enzoselenazolium iodide The above ,cyclammonium quaternary cyanine dye salt intermediates are well-konwn to the art, and hence the methods for their preparation need not be discussed herein. While the above dye intermediates are disclosed as being in the form of the preferred ethiodides, it is to be understood that they may also be employed in the form or the other quaternary salts previously mentioned.

As acid binding. agents employed for the prep araltion of the dyes of the present invention, the following may be advantageously employed: pyridine, methylpyridine; dimethylpyridine, ethylpyridine, ethylmethylpyridine, trimethylpyridine, quinoline, and thelike, containing a tertiary aliphatic base such as triethylamine, tripropy1a-.

mine, tributyla'mine, etc., as a catalyst. The tertiary base may also include, if so desired, a small quantity of acetic acid or acetic anhydride. In

' general, the amount of condensing (acid binding) agent used may vary within wide limits, e. g., from 1 to 25 mols. Concentrations ranging from 1 mol to about 15 mols are'preierred.

In the preparation of these new trinuclear cyanine dyes, the Z-amino-5-methyl-3,4-diazole and 2-amino-5-methyl=1,3,i-triazole bases are converted into their corresponding alkyl 'or I to -Shouts.

aralkylsquaternanysaltsxhy'heating: theibaseiwlth reaotiirezgroups;hamely aminozandmethyhgroups.

am'alkyl on'aralykylihalide: usually employed. in The: acetone insoluble; portiomisrthmlghtxtoz bee such: a'reaction; im a bomb: or sealedi tube ati-arz amino-lls-ethylifiimethyl -l',3;4-thiadiazoIliun= temperature; ranging: from 100 $01120? for: 3% iodide, and: is: incapables of: undergoing a: cone densatiom reactiom through both the; amin'w'andir The quatennization' o'f the:diazole basmmusti-bei I methyligrmtpsl; mama, however, undergmeucom carefmly icontrolled otherwise ani undesirable: den'sationisreaction 'thrmigh. the amino? groups quantity onthelisomecie fomn-oi:tnequat-emasy onlya: 1 salt-is obtained. lt' is believed thatithe reactive r Emplesm formsleading to thetrinuclean'cyanine dyes-ofthe lot: 1 present invention; the followingz oonflguraw 7 tiom: R rH2N=- -Gi,g -G-CHJ: E

1\ v I "H v I 4 X I; y t yyly 4 nadiazolinium iodide As aiby-product (isomeric form) of'thisi rea'ce tion; a: second quaternary. salt'is isolated, which v probably has the following configuratiom. mimefthyl-LsA'thladiazole Example I was repeated with the exception that an equivalent quantity of 2-amino-5-methyle 1,3i4 'oxadiazole was substituted for 2-amino-5'- R i Ewample lII l N e X HEN- their? v I V SEN-C 6 0K This by-product not-useful in the prepare. I I r tion of the dyes of=- thegpresent inventiom. since; V 51m I r H it undergoesdye condensations only-through-the 1 ,7 amino group; I 7 3o 1,4-diethyl-g amlnofi methyl-l, A-tnazolium iodide The following examples describe, indetail; the: Examplerl wasrepeatecbwithsthezexception that method: for preparing the quaternated diazoles;e ale-equivalentquantity of: l ethyle2-amino-5' and; triazoles-, .,and the trinuclear cyanine, d-yes methyl 1,3,4 -triazole was: substituted for. 2- therefrom, but it is to be understood that they amino-5-methyl-1,3,4-thiadiazole.

are presented merely for the purpose of illustra- While: the aboveadiazolimum salts have been tion and are not to be construed as limitative. prepared in the form of the preferred iodides, it

Example I 1- is to be understood that they may also be prei pared? in, the form containing other anionic acid radicals. For example, instead-of employing ethyl H 40 liidideastliequaternatihg'agent, methyl, ethyl;

S I the like may also be employed.

2-amino-4-ethy1-5-methyl-1,3,4-thiadiazo1ium iodide The preparation of the trinuclear cyanine dyes,

mixture of 6 grams: of: 2 amino-5-methyli whileutilizihg. thediazolimumisalts asiabove pre= a v or propyl chloride, bromide, dimethyl" sulfate, j J benzyl bromide, methyl-p-toluene sulfonate, and 3 1,3,4-thiadiazole and 15 grams. on ethyl iodide: DM'BdaiSQillllStBfirtdPbE thefollowing', examples;

Example IV as." I an,

was heated in a sealed bomb, the temperature one" gram of 2-amino-4-ethyl-5-methyl-1,3,4-

being carefully controlled in the range of thiadiazolium iodide and 2 grams of 2 L-aceta 103 111?" Ci, ford'hours; Uponcoolifig, the'prodr anilidovinyl')f-3 ethylb'enzo-thia'zoliunf iodide not was filtered and t'h'e' residue" extracted with? iwere dis'solyed' in" 20" cc; of pyridine and 2* cc." of seyeral2"cc'. portionsof'anhydrousiacetone'untll"60 triethylamineadd'ed. The mixture was heated about 20 cc; had been consumed; The acetone? to reflux for 5 minutes, cooled, and diluted with extract was precipitated with anhydrous ethylf several volumesof waterl" The green crystals" ether and dried. The dried" product is useful m: whichseparatedout were filtered ofi andirecrys-f, preparinglthe trinuclear'cyaninedyes of the pres-'- ta'l'lized" from ethyl aleohol; The dyesensitized f entinventi'on, since the" condensation reaction isf a s'iWer bromoiodid'e emulsion to my; with ajl simultaneously brouig'ht about through the two maximum at 680 m one gram'of. 2-amirioQ4-ethyl-5-methyh1,3,4

thiadiazolium iodide and.2.0 grams of 2-(fi-acetanilidovinyl) -3-ethylbenzothiazolium :;iodide weredissolved in 20. cc. of pyridine and 2 cc..'of

triethylamine added; The mixture washeated over steam at C., for -30jminutes, cooled, and diluted with about cc...of water. .The leafy crystals which separated out were filtered, and recrystallized from thylialcohol. The dye crystals were dissolved in methanol and precipitated as the perchlorate dye salt and purified by several crystallizations froiif'methyl alcohol. The dye sensitized a silver-bromoiodide emulsion to 670 ml. with a maximum at 620 m Example VI Six grams of Z-methylmercapto-l-ethyl-G- methyl quinolinium iodide and 2 grams of 2- amino-4-ethyl-5 me'thyl-1,3,4 thiadiazolium iodide were dissolved in cc. of pyridine and 1 cc. of triethylamine added. The mixture was heated over steam for 1. hour, cooled, and diluted with water. The crystals which separated 'out were filtered off and recrystallized from N-butanol. The dyesensitized a silver-bromoiodide emulsio to 610 m -with a maximum at560 m r ExampZeVII f p CzHa Two grams of Z-amino--etliyl 5 methyl l,3,4- thiadiazolium iodide and-8 grams of'-2 -(fiacetanilidovinyl) -3 thyl-5,6-methy1enedioxy benzothiazolium iodide were dissolved in 60 cc. of pyridine and 2 cc. of triethylamine' a'ddedf The mixture'was heated under reflux for 35 minutes, 3 cooled, and diluted with water." The crystals which separated out were filtered oif and recry'stallized from methanol. The dyesensitized 'a silver-bromoiodid'e emulsion'to' 740 mji; with "a maximum at 700 m 5 5 p Example vm CgHs .Five grams of '2-(p-anilidovinyl) 3+ethyl-4,5e. diphenyl thiazolium iodide and 1.4 grams oi 2-.

amino-i-ethyl- 5 methyl 14.3.4 thiadiazolium iodide were dissolved in 50 .cc; of pyridine con-; taining 2 cc. of triethylamine and 1 cc. of acetic anhydride; The mixture was heated under reflux for- 5 minutes, cooled, and diluted with water. Thezcrystals which separated out were filtered 011 and. recrystallized. from ethyl alcohol. The. 10. recrystallized product was dissolved in methanol and precipitatedas the perchlorate dye salt; The

dye sensitized a silver-bromoiodide emulsion, to

685 m with a maximum at 635 m an; an.

One gram of Z-methylmercapto- 3-ethyl-ben- 25 zoselenazolium iodide and 0.3 gram of 2-amino- 4-ethyl-5-methyl-1,3,4-thiadiazolium iodide were dissolved in 10 cc. of pyridine containing 1 cc.of

triethylamine. The'mixture was heated over an 1 open flame to drive off the mercaptan' by-product.

30 The reaction mixture was diluted with'wa'ten-and the dye which precipitated was filtered off and converted to the bromide salt. The dye was purifiedand crystallized. from ethyl alcohol. The dye CH: I"

sensitized a silver-bromoiodide emulsion to 520 V mu, witha maximum at 480 in V m Y a.

Six grams of 2-methylmercapto-3eethyl-5,6 di

0 methoxy benz'oselen'azolium p-tolu'enesulionate and. 2.7 grams of 2-amino-4-ethyl-5-methyl- 1,3,4-thiadi'aZoIiumiodide were dissolved in 50 cc.

ofpyridine and 2 cc. of triethylamirle. The mixture washeated over steam for 1 hour, cooled, and diluted with" 2"volumes of water. The yellow crystals? which separated out were filtered off and recrystallized from .methanol after conversion 7 to the bromide salt. Thetdyeasensitiaed a silveribromoiodide emulsion to 530m with a maximumat 480 m 7 .Emmplezxl You; v on; One gram of 2-methylmeroapto-3-methyl- 4(p)-tolyl-5-phenyl thiazolium iodide and 02 gram of 2-amino-4-ethyl-5-methyl-1,3,4-thia A diazolium iodide were dissolved in 10 cc. of pyridine and 1 cc. of triethylamine added. Thermixture was heated under reflux until the methyl mercaptan by produc'ti was 'dissipated. After cooling anddilutingwith-waterfthereaetionmixture was filtere'd' and the orange orystals recrystallize'dirom methanol-"until pure. The dye sensitized a --silver=bromoiodide emulsion to "530 III/.0, with a maximum at 480 m One .1 gramiof ,2 methylmerca ptoaeth-yl .Hac

benzothiazolium iodide and 0.25 gram of Z-amino- 4-ethyl-5-methyl-1,3,4-thiadiazolium iodide were dissolved-Lin 10.c'c. dfmyridine eontailiing 1 CCfdf rtrie'thylamine. 'Lhemiixture "was heated' under xrefluxluntil the:methylnnercaptan was dissipated. Afters'cooling fithe reaction mixture and diluting with"= water, the crystalline 'dye was filtered and purified =by="crys'tallization from methanol. dye sensitized ia siiver bromoio'dide emulsion to 510 m,u, -W-ith=a, maximum at i'm m l I i Example-XIII The 7 T0 ing 0.1 cc. of acetic anhydride and 0.1 cc. of triethylamine. The mixture was heated under reflux for 1 minute, cooled, and diluted with water.

The crystals=whichseparated out were dissolved in methanol and .the dye converted to the perchlorate salt, and then purified by recrystallizin from methanol. The dye sensitized a silverbromoiodide=emulsion to 730 -mu, with a maxi- ,mum at 690 m Example XIV t? Y C=GH- CH=NC- .o- .cH =oH-oH=o One gram of -2"(13-'acetanilidovinyl)=3-ethylbenzoselenazolium iodide and 025 'gram of 2- 30 amino =4 -eth;yl --5 --methyl "1 3,4 thiadiazoliumiodide-*wenydissolved in 25 "cc; of pyridine containing '1 cc. of triethylamine. The mixture was *heated "under reflux for 3 minutes, cooled, and the dye precipitated by the addition of 2 volumes of ether. The separated residue was washed several times with water while allowing the tacky: solidto'gradually solidify before filter- -'ing. The solid was then purified by boiling out with several ,5 ccrportions of methanol. The final residue was crystallized several times from methanol to obtain the pure dye. The dye sen- :sitized :a silver-#bromoiodide :emulsion to 730 m with *a maximumat 680 m (Lethal-on:

One gram of .2-(fi-anilidovinyl)-3-ethyl-6- methoxy benzoselenazoliumliodide and 0.25 .gram of 2-aminoA-rthyl-lf)emethyl-1,3;4 thiadia2olium iodide were dissolved inlz c. .oi pyridine contain atesalt by the addition of an aqueous solution ..-of ,potassium perehlora-te. .The-rcrystals which '--.separated .out --were ,filtered ofi -and recrystal- .lized from ethyl alcohol. The dye sensitized'za silver-bromoiodide emulsion to 680 me, with a maximum at 620 m -12 Example XVIII Four grams of Z-(p-anilidovinyl)-3-methyl- 2-amino-4-ethyl-5-methyl- 1,3,4 thiadiazolium thiazolinium iodide and 1.5 grams of 2-amino-4- ethyl-'5-methyl-1,3,4-thiadiazolium iodide were dissolved in 15 cc. of pyridine containing 1 cc. of

acetic anhydride and 3 cc. of triethylamine. The mixture was gently heated on a steam bath for several minutes, cooled, and the dye precipitated by the addition of 2 volumes of ether. The precipitate was dissolved in an adequate amount of hot water and the oily impurities separated. The aqueous solution of the dye was precipitated as the perchlorate salt by the addition of an aqueous solution of potassium perchlorate. The periodide were dissolved in 5 cc. of pyridine containing 0.5 cc. of triethylamine and 0.5 cc. of acetic anhydride. The mixture was heated under reflux for 3 minutes, after which time 1 cc. of triethylamine was added and the mixture heated for an additional 2 minutes. Upon cooling, the dye crystals were precipitated by, adding 2 volumes of ether to the reaction mixture. The dye crystals which separated out were filtered ofifand recrystallized from methanol. The dye sensitized a silver-bromoiodide emulsion to 660 ma, with a maximum at 630 ma.

Example XIX chlorate solution which separated out from the aqueous solution was filtered off and recrystallized from n-butanol. The dye sensitized a silverbromoiodide emulsion to 650 mp, with a maximum at 600 m Example XVII Four grams of 2-(p-acetanllidovinyl)-3-ethyl- 5,6-dimethyl benzoxazolium iodide and 1.5 grams of 2-amino-4-ethy1-5-methyl-1,3,4 thiadiazolium iodide were dissolved in cc. of pyridine con- 45 taining 2 cc. of triethylamine. The mixture was 02H: methanol. The dye sensitized a silver-bromoiodide emulsion to 720 m with a maximum at 690 ma.

heated under reflux for 5 minutes, cooled, and diluted with 2-3 volumes of water. The dye which separated out was filtered off' and recrystallized from methanol, redissolved in methanol and reprecipitated out as the perchlorate salt by the addition of an aqueous solution of potassium perchlorate. The perchlorate dye crystals were further purified by recrystallizing from methanol. The dye sensitized a silver-bromoiodide emulsion to 680 m l, witha maximum at 630 mp.

One gram of 2-(B-acetani1idovinyl) -3-ethyl- 5-phenyl benzoxazolium iodide and 0.25 gram of 2-amino-4-ethy1-5-methyl-1,3,4 thiadiazolium iodide. were {dissolved in :12 "cc. of :pyridine .containing 1 cc. of triethylamine and 0.-5;c,c. :0f -acetic anhydride. The mixture was heated over a steam bath for 5 minutes, cooled, and diluted with 3 volumes of water. The crystals-which separated tout were filtered 501T and mecrystallized from a "methanol as the perhlora'te-salt. \The dye sensi-'- tized a silver-bromoiodide emulsion "to 660 m, with a maximum at 610 my.

Example XXI One gram of 2-(fi-aoetanilidovinyl) -3-ethyl-5- methoxv benzoxazolium iodide and 0.3 gram of zHs 52-am'ino- '4-ethy1--5 -'methyl 1,354 =thiadiazo1ium iodide were dissolved in 10 cc. of pyridine-con taining 1 cc. of triethylamine and the solution agitated with a; glass rodior 30 minutes at room temperature. The dye in solution was precipitated by the addition of ether. "The liquor was decanted and the residuewashed 'with water and thendiss'lvedinedld methanol. :Onefcc. of fa"20% --aque ous solution=of sodiumeperchlorate was added to i the filteredimethanolssolution. 'Thetrinuclear l dye preoipitated asethe perohlora'teisalt andwa's purified by recrystallizing from ihot methano The dye sensitized a silver-bromoiodideemulsion to 650 m with a maximum at 560 m H Ewamz'ile. XXII C iHs ..:dilutedwithseveral-volumes of water. -'1he.orystals which separated out were filtered of! and re- :.crystallized from methanol. The dye sensitized asilveig-bromo-iodide emulsion to 720 m with a maximum at 690 mu. ,Eaiample XXIII Example XXII was reneated with the exception that 023 gram of 2-amino-4-ethyl-5-methyl- 1,3,4 0xadiaz01ium iodide was substituted for 0.3

" gram of 2-amino-4-ethyl-5-methyl-1,3,4-thiadiiazolium iodide.

. Example-XXIV Example repeated with the exception v.that an equivalent "amount -of 1';4-diethy1-,2+

amino-5-methyl-'1;3,4-triazo1ium iodide was sub? I it'hese rtrinuclearvcyanineidyes, the dye may taining 1 do. of triethylam-ine. The mixture was W5 dissolyeidzininiethylxoriethylialoohol andfithemed- 18 16 holicsolutioncontaining' from 5 to 50 milligrams l. 2. A trinuclear cyanine dye corresponding to of the dye added to a-liter of emulsion; While in the formula: I V

., .4 V I. v I S a 5 v S C=CHGH=N\/ o-on=oH-c11=c I rs N W 431B ihfls genera practiceit may not be necessary to add 7' v 3. A trinuclear cyanine dye corresponding to the dye in the amounts larger than those above the formula:

/ N i i 7 HzC CH:

CIHI 1, C2115 given, generally, for satisfactory results, amounts 4. A trinuclear cyanine dye corresponding to ranging from to 50 milligrams are sufficient to the formula; j

02H; 4- V s\ N 1 V /s o=oH-oH=N-t: i ,-on=cn-cn=o r- I 02H: 02H: 7 :Hs

obtain the maximum sensitizing effect. However, 5. The method of producing trinuclear cyanine we do not wish to limit our invention to the quandyes which comprises condensing in the presence tities just indicated as the most suitable amount of an acid binding agent two mols of a compound will, in each case, be found by a few comparative of thegeneral formula:

experiments. The dyes may be added to the 'A emulsion in form of solutions. Suitable solvents as indicated in the examples are the alcohols, for N (0114311) instance, methyl or ethyl alcohol which may be anhydrous or diluted with a small volume of with one mol of a compound of the :general water. In actual practice, the dyes are applied to 40 formula: I I

theemulsion during any stage of its production. I R t However, they are preferably added to the flni N '1|\1 ished emulsion before coating. N H

, While there have been pointed out above certain preferred embodiments of the invention, the same is not limited to the foregoing examples, wherein A is the residue of a heterocyclic nitrogiIIustrations or to the specific details given thereenous compound of the type used in the preparain, but is capable of variations and modifications tion of cyanine dyes, R represents a member as to the reactants, proportions and conditions selected from the class consisting of alkyl and employed. Accordingly, it,is intended that the aralkyl groups, R1 represents a member selected invention be defined only-by theaccom'panying from the class consisting of anilido, alkyland claims, in which it is intended to include all feaarylmercapto groups, R1 being anilido only when tures of patentable novelty residing therein. m is 1 and 2 and alkyl and aryl mercapto when We claim: V m is 0, X represents an anionic acid radical, Y

1. Trinuclear cyanine dyes characterized by the represents a member selected from the class confollowing general formula: sisting of oxygen, sulfur, and NR2, wherein R:

wherein A is the residue of a heterocyclic nitrogis a member selected from the class consisting of enous compound of the type used in the preparahydrogen and alkyl groups, 111. represents a tion of cyanine dyes, R. represents a member senumeral taken from the group cbnsisting of 0} lected from the class consisting of alkyl and i 1, and 2, n 1 r pr sen a numeral taken from aralkyl groups, X represents an anionic acid radithe group consisting of 0 and 1. cal, Y represents a member selected from the The method of Producing trimlclear y ne class consisting f oxygen, ulfur and dyes which comprises condensing in the presence wherein R2 is a member selected from the class of-an and binding agent two mols of a compound consisting of hydrogen and alkyl groups, m repof the formula:

resents a numeral taken from the group consist- V ingof 0, 1, and 2, and 1) represents a numeral RN/ C(CH=CH M-Rl taken fromthegroup consisting. of 0 and 1. Eli-0 wherein A is the residue of a heterocyclic nitrogenous compound of the type used in the preparation of cyanine dyes, Rrepresents a member selected from the class consisting of alkyl and aralkyl groups, R1 represents a member selected from the class consisting of anilido, alkyland aryl mercapto groups, R1 being anilido only when m is 1 and 2 and alkyl and aryl mercapto when m is 0, m represents a numeral taken from the group consisting of 0, 1, and 2, p represents a numeral taken from the group consisting of and 1, and X represents an anionic acid radical.

7. The method of producing trinuclear cyanine dyes which comprises condensing in the presence of an acid binding agent two mols of a compound of the formula:

v RI with one mol of a compound of the formula:

and 1, and X represents an anionic acid radical.

8. The method of producing trinuclear cyanine dyes which comprises condensing in the presence of an acid binding agent two mols of a compound of the formula:

18 with one mol of a compound of the formula:

Ih s if"? 5 H,N-o N c-om 1- wherein A is the residue of a heterocyclic nitrogenous compound of the type used in the preparaaryl mercapto groups, R1 being anilido only when m is 1 and 2 and alkyl and aryl mercapto when m is 0, m represents a numeral taken from the group consisting of 0, 1, and 2, p represents a numeral taken from the group consisting of 0 and 1, and X represents an anionic acid radical.

9. The process of producing trinuclear cyanine dyes which comprises condensing in the presence of an acid binding agent 2 mols of 2- (p-acetanilidovinyl)-3-ethyl-benzothiazolium iodide with 1 mol of 2-amino-4-ethyl-5-methyl-1,3,4-thiadiazolium iodide.

10. The process of preparing trinuclear cyanine dyes which comprises condensing in the presence of an acid binding agent 2 mols of Z-(p-acetanili- 3 dovinyl) 3 ethyl 5 methyl-benzothiazolium iodide with 1 mol of 2-amino-4-ethyl-5-methyl- 1,3,4-oxadiazolium iodide.

11. The process of preparing trinuclear cyanine dyes which comprises condensing in the presence of an acid binding agent 2 mols of 2-(p-acetanilidovinyl)-3-ethyl-benzothiazolium iodide with 1 mol of 1,4-diethyl-2-amino-5-methyl-1,3,4-triazolium iodide.

ALFRED W. ANISH.

0 CHARLES A. CLARK.

REFERENCES CITED The following references are of record in the 5 file of this patent:

UNITED STATES PATENTS 

